Related Field
Various embodiments of the present invention relate to a method for additive manufacturing of three-dimensional articles.
Description of Related Art
Freeform fabrication or additive manufacturing is a method for forming three-dimensional articles through successive fusion of chosen parts of powder layers applied to a worktable. A method and apparatus according to this technique is disclosed in US 2009/0152771.
Such an apparatus may comprise a work table on which the three-dimensional article is to be formed, a powder dispenser, arranged to lay down a thin layer of powder on the work table for the formation of a powder bed, a ray gun for delivering energy to the powder whereby fusion of the powder takes place, elements for control of the ray given off by the ray gun over the powder bed for the formation of a cross section of the three-dimensional article through fusion of parts of the powder bed, and a controlling computer, in which information is stored concerning consecutive cross sections of the three-dimensional article. A three-dimensional article is formed through consecutive fusions of consecutively formed cross sections of powder layers, successively laid down by the powder dispenser. Further details regarding the controlling computer, which may be utilized in certain embodiments to in part or in whole implement the method described herein may be found in the detailed description provided herein.
There is a tendency when fusing a cross section of the three dimensional article with small dimensions, i.e., when using a shorter scan line length than a predetermined value, that material characteristics is worse compared to cross sections of the same three dimensional article with larger dimensions, i.e., when using a longer scan line length than the predetermined value. The degraded material characteristics for the small dimensions may be caused by porosities and/or incomplete fusion in the material.